1. Field of the Invention
The invention relates to a test-piece manipulator and a corresponding cylindrical test piece with standard defects.
2. Prior Art
Test pieces with a corresponding manipulator are standards for adjusting ultrasonic test systems for tubes, bars or material with a regular polygonal profile. Ultrasonic test systems of this type will be referred to here as "whole-body test systems." The equipment consisting of the test-piece manipulator and the test piece is used to set the test mechanics and test electronics of such whole-body test systems. The test pieces (calibration standards) are precisely positioned in the whole-body test equipment by the test-piece manipulator.
Test pieces usually have several types of defects, depending on the test function. These defects are incorporated in different positions on the circumference and length of the test piece. To be able to detect all such defects (standard defects), it must be possible, on the one hand, to move the test piece into each position in its longitudinal axis relative to the whole-body test equipment. On the other hand, it must be possible to rotate it about its longitudinal axis and to perform oscillation movements, if necessary.
Standards and, in some cases, delivery contracts prescribe the intervals at which a whole-body test system must be tested to maintain predetermined production quality. For example, the probes become contaminated or worn during operation. To obtain the same electrical displays for the same defects in all cases, it may be necessary to adjust the amplification. Other tests of the system itself are necessary from time to time.
This type of testing and adjustment of a whole-body test system always means a loss of production. Therefore, an effort must be made to keep the adjusting and testing time as short as possible. To accomplish this, it is necessary to change test pieces quickly and with the greatest possible automation.
The term whole-body test system is defined here as a system for testing tubes, bars or regular polygonal profiles, in which the profile to be tested is moved axially. In addition, a rotary movement is performed, in which either a rotor is rotated about the axis of the profile (test piece) to be tested, or the test piece itself is rotated. In both cases, helical test tracks are obtained. Test systems of this type are described, for example, in J. and H. Krautkramer: Werkstoffprufung mit Ultraschall [Materials Testing with Ultrasound], 4th ed., pp. 442-461.
In the practical course of an adjustment of a whole-body test system, the rotor or probe carrier is generally moved from the test position into a service position; this is performed horizontally. In this position, a test piece is moved into the rotor or probe carrier by the test-piece manipulator.
Test-piece manipulators currently in use have a chuck of the type also used in turning and drilling machines. The test pieces themselves are tubes or bars, possibly comprising several partial sections. Division into several partial sections is necessary when defects are to be introduced into the test pieces from the inside.
DE-B-1182931 describes a coupling on machine tools, especially milling and drilling machines, for clamping and releasing tools. This coupling is provided with a spindle, which forms a conical counterpart at its forward end and through which a threaded clamping rod passes. The shafts of the tools have a cone with internal threading, into which the clamping rod can fit.
Setting a test system with the previously known test-piece manipulator and the accompanying test pieces requires a relatively great amount of time. The test pieces cannot be inserted by an automatic machine, e.g., a robot, into the chuck or the previously known test-piece manipulator and centered, but rather manual alignment is necessary. For this reason, the previously known test pieces are also provided with a grip or projection on their free end region when they are clamped in, which allows better centering in the chuck.
Proceeding on the basis of this state of the art, the goal of the invention was to develop a test piece and a corresponding test-piece manipulator, which allows automated insertion of a test piece in the manipulator, thereby creating a situation in which the test pieces can be drawn from a magazine mechanically, clamped into the test-piece manipulator and run into the test equipment without the agency of a human being.